WATER AFFAIRS OR WATER DESPAIR.
The quality of water in our rivers is deteriorating faster than the price of petrol is going up.
Send your comments to Water Despair - 4_babich@fishingowl.co.za
The following release was prepared by Keith Wallington.
To download the word doc
click here
Keith works closely with the Yellowfish Working Group and the Orange/Vaal River Yellowfish Conservancy. Keith also sits on the Barrage Forum Management Committee together with the Department of Water Affairs and Rand Water (the Barrage Forum is chaired by Francois van Wyk, head of Catchment Management for Rand Water).
083 212 1884
JOHANNESBURG
21 January 2006
Fish kills on the Vaal River, what are the facts? The Yellowfish Working Group seeks to bring some clarity.
The recent fish kills on the Vaal and Klip rivers have generated significant media exposure and subsequently fuelled much response and debate from people across the spectrum: environmentalists, the legal fraternity, anglers, politicians, and civil servants, in fact it seems everyone has in some way been upset by what happened whether they are directly impacted or not. There are a few facts that, when tabled clearly, will hopefully allow the public to develop a more balanced view of what actually happened.
Two fish kills occurred with dead fish being sighted from 19-21 January, although some carcasses may still be travelling downstream and assumed to be more recent kills. These fish kills occurred in two specific areas and not along the length of the Middle Vaal River as has been implied in some reports. One of the fish kills occurred at the confluence of the Klip River and the Vaal River at the Barrage. The primary reasons for this kill are at this point believed by Rand Water and DWAF (amongst others) to be due to the simultaneous influx of untreated sewage and the “stirring up” of organic matter from the substrate of the river. The sewage influx is an ongoing problem in the Klip River as well as one of its tributaries, the Riet River. Raw sewage and large amounts of organic material have the combined effect of depleting the dissolved oxygen in the water which fish require to breath resulting in fish (and other aquatic animals) suffocating. Typically this polluted water is diluted and degrades as a threat to aquatic life after entering the Barrage. By the time the water has passed over the Barrage wall and into the Vaal River below, the water is diluted and not dangerous to water users (boaters, anglers and other people in contact with the water) and aquatic life downstream.
The second fish kill occurred at the weir near the Leeudoringstad bridge downstream of Orkney in the North West Province. This fish kill occurred for much the same reasons as the kill in the Vaal: Here the untreated sewage entered the Vaal via the Schoonspruit. The large mass of decomposing vegetation building up on the substrate in this weir (apparently resultant from water hyacinth that had been killed via herbacide spraying) was “stirred up” into the water column by high flows, caused by the heavy rains, and subsequently acted in concert with the sewage water to deplete the dissolved oxygen in the water resulting in fish suffocating.
Eye witnesses noted large numbers of dead fish at both sites (Klip/Barrage and Leeudoringstad). The species most noted were Smallmouth Yellowfish (Labeobarbus Aeneus), Largemouth yellowfish (Labeobarbus Kimberleyensis which is listed as Vulnerable on the IUCN Red List of Threatened Species) and a variety of carp species. Sharptooth Catfish (known colloquially as “Barbel”) are less likely to suffocate in these conditions as they are capable of breathing air via a primitive lung.
Fish kills of this size are indeed a tragedy and all stakeholders must come together to find solutions to the causes, while in parallel ensuring that the facts are clearly reported avoiding inappropriate finger pointing and panic.
South Africa has for some time faced a growing crisis in the rapidly declining state of its sewage processing installations. While most municipalities plead poverty when asked why they have not kept their sewage processing capability abreast with the rate of residential development this is only a portion of the problem: A large amount of storm water enters the sewage systems through illegally connected piping: this means that when storm water, especially in very high rainfall such as that experienced at the time of these fish kills, enters the sewage system it enters the sewage works in volumes far in excess of what the sewage works is designed to manage. The result is raw sewage moving through the sewage works extremely quickly and entering the river on which the sewage works is positioned, still in a raw state.
Establishing a single party to blame for these fish kills is not simple as multiple factors have resulted in the kills: Storm water being directed into sewage works illegally by unscrupulous developers; decrepit sewage works already running at full capacity due to massive residential development and insufficient budget or skills apportioned to upgrading capacity; high volumes of organic matter decomposing on the substrate of the river being lifted into the water column by flood level water flows. All of these factors converge to deplete oxygen and suffocate fish.
Misinterpretation of the facts has created panic amongst landowners along the length of the Vaal and its tributaries where many have assumed the fish kills span the entire river system from the Barrage to Bloemhof Dam: This assumption is believed by the YWG to be incorrect, the kills were isolated to the areas mentioned above and at the time of writing the YWG is aware of no fish kills outside of these areas. The Vaal Dam was not affected as it lies upstream of the Barrage. The stretch of river between the Barrage and Orkney is also not affected although dead fish from the Barrage fish kill may make their way downstream with the normal flow of the river.
ENDS
About the Yellowfish Working Group (YWG)
Founded in 1997 by the Federation of South African Flyfishers (FOSAF) this body was formed to conserve the yellowfish of South Africa as indicators of good water quality: This objective is met through education, protection and promotion of yellowfish as a world class angling species. The YWG is driven by a coming together of the angling fraternity, conservationists, government and other interested parties.
